The bleaching method using inorganic peroxides such as sodium perborate tetrahydrate, sodium perborate monohydrate, sodium percarbonate, urea peroxohydrate, or sodium peroxide enables to remove contaminants such as stains from fruit juice, coffee, wine, or sap more effectively, i.e., stains. However, the bleaching ability of the inorganic peroxide significantly varies depending on the temperature. For example, sodium perborate shows optimum effects at higher than 80° C., and sodium percarbonate at higher than 60° C. But both are not effective in the cool water, i.e. at 20 to 25° C. in summer or at about 5° C. in winter. Thus, bleach activator method was introduced for inorganic peroxides to present comparable bleaching effects even at a low temperature.
Even though TAED (tetra acetyl ethylene diamine) is most commonly used for the purpose of activating a bleach, it is not effective in removing oily stains such as sebum. U.S. Pat. No. 4,412,934, No. 4,483,778, No. 4,606,838 and No. 4,671,891 disclose bleaching agents using acyl compound as a bleach activator, but it is not cost effective because it need to be used in plenty. And U.S. Pat. No. 4,686,061, No. 5,043,089 and EP No. 0210674 disclose a bleach activation of carbonate derivatives, but it leaves bleach odor because its molecular structure is changed in laundry water. Moreover U.S. Pat. No. 4,179,390, No. 4,259,201, No. 5,098,598, No. 5,520,844, and No. 5,575,947 disclose many organic peroxycarboxylic acids as bleach activators, but these bleach activators are unstable in heat and thus tends to lose an active oxygen of them. In order to solve such problem, a technique for coating and granulating organic peroxycarboxylic acid is introduced (see EP No. 396,341 and EP No. 256,443). However, this technique is bad with regard to economical efficiency, and decreases aqueous solubility to make the bleach activator remained in the cloth.
With the reasons above, an ester bleach activator is preferred since it is capable of releasing peroxycarboxylic acid for activating a bleach together with inorganic peroxides only in a wash water, particularly releasing peroxycarboxylic acid even at low temperature, has storage stability to make long time storage possible, shows excellent bleaching power against hydrophobic stains as well as hydrophilic stains, and rarely makes bleach odor.
U.S. Pat. No. 5,705,091 discloses such an ester bleach activator compound. However, the ester bleach activator compound is made under the conditions: 1) argon gas is used when phosgene is added for reaction, and the reaction temperature should be controlled low at about −78° C., and 2) hydroxybenzene, its derivatives, or its salts are added and reacted in an organic solvent such as methylcyanide (CH3CN). Thus, the above technique disadvantageously requires very complex manufacturing procedure and shows low yield as much as about 50%.